package com.finch.nio2;

import org.junit.Test;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.nio.file.Paths;
import java.nio.file.StandardOpenOption;

/**
 * @author Levi Wang
 * @create 2021-07-14 22:23
 *
 *一、使用NIO完成网络通信的三个核心
 *
 * 1、通道(Channel): 负责连接
 *   java.nio.channels.Channel接口：
 *      --SelectableChannel
 *          --SocketChannel
 *          --ServerSocketChannel
 *          --DatagramChannel
 *
 *          --Pipe.SinkChannel
 *          Pipe.SourceChannel
 *
 * FileBuffer不能非阻塞方式
 *
 * 2、缓冲区(Buffer): 负责数据的存取
 *
 * 3、选择器(Selector):是SelectableChannel的多路复用器。用于监控SelectableChannel的IO状况的
 *
 *
 *阻塞方式
 * 注意：要先启动服务端，再启动客户端
 *
 */

public class TestBlockingNIO {

    //客户端
    @Test
    public void client() throws IOException {
        //1. 获取通道
        SocketChannel sChannel = SocketChannel.open(new InetSocketAddress("127.0.0.1", 9898));

        FileChannel inChannel = FileChannel.open(Paths.get("1.jpg"), StandardOpenOption.READ);

        //2. 分配指定大小的缓冲区
        ByteBuffer buf = ByteBuffer.allocate(1024);

        //3. 读取本地文件并发送到服务端去。需要FileChannel
        while (inChannel.read(buf) != -1){
            buf.flip();
            sChannel.write(buf);
            buf.clear();
        }

        //4. 关闭通道
        inChannel.close();
        sChannel.close();


    }



    //服务端
    @Test
    public void server() throws IOException {
        //1. 获取通道
        ServerSocketChannel ssChannel = ServerSocketChannel.open();

        FileChannel outChannel = FileChannel.open(Paths.get("2.jpg"), StandardOpenOption.WRITE, StandardOpenOption.CREATE);

        //2. 绑定连接
        ssChannel.bind(new InetSocketAddress(9898));

        //3. 获取客户端连接的通道
        SocketChannel sChannel = ssChannel.accept();


        //4. 分配指定大小的缓冲区
        ByteBuffer buf = ByteBuffer.allocate(1024);


        //5. 接收客户端的数据，并保存到本地
        while (sChannel.read(buf) != -1){
            buf.flip();
            outChannel.write(buf);
            buf.clear();
        }

        //6. 关闭通道
        sChannel.close();
        outChannel.close();
        ssChannel.close();

    }

















}

























